i think the fallout of sharon shooting/potentially killing cap is going to be a main focus in the actual captain america title, and i highly doubt she'll stumble out into the new avengers.
bendis said that the new ronin has a history of changing their appearance/name/i-don't-remember-the-exact-quote with their mindset. sharon carter doesn't fit. falcon doesn't fit, either, unless you want to count his costumes. and i doubt bendis would say something that blunt, then chicken out with "i was talking about his costumes!"
hawkeye's still definitely in the running, and so is bucky. i just doubt bucky'd say "yo"... but that's how i'm eliminating all the choices.